Hole digger

ABSTRACT

The present invention relates to post hole diggers. In particular, the present invention describes a post hole digger that constructs uniform diameter holes. The post hole digger of the present invention is comprised of a pair of handles, digging scoops and a hinge bracket. The hinge bracket translates the movement of the handles into movement of the scoops. The hinge bracket restricts the movement of the handles as digging occurs, allowing for the construction of a relatively straight-sided posthole, essentially removes the tapering of a hole as the hole becomes deeper.

FIELD OF THE INVENTION

[0001] The present invention relates to hole diggers. In particular, theinvention describes a posthole digger that makes uniform diameter holes.

BACKGROUND OF THE INVENTION

[0002] The post hole diggers generally in use today are the type wherethe digger is thrust into the ground and the handles are pulled apart toclose the blades and scoop out the dirt. As the hole becomes deeper theupper portion of the hole becomes progressively wider. A three-foot deephole made with a traditional hole digger with a scoop end of only fiveinches must be opened up ten to eleven inches at the top. The holecreated will be tapered which will create a lack of ground support whenconcrete is used to keep the post in position.

[0003] There are some prior art devices that allow the digging of aposthole of constant diameter. U.S. Pat. No. 6,089,632 to Pickrenpresents a device wherein the handles cross instead of separating whenpulling out dirt. The movement of crossing the handles iscounter-intuitive and there is some danger of trapping or pinching onesfingers between the crossing handles. Also the device of the U.S. Pat.No. 6,089,632 patent has an increased number of pieces such as two hingebrackets, mounting plates for handles and shovel blades which rendersthe device more difficult to repair and maintain.

[0004] The U.S. Pat. No. 5,427,424 to Robinson teaches a device with asingle handle also capable of digging a constant diameter shaft. Thedevice has a complex design with many sections and parts. Once more thedevice is awkward to use and with many parts subject to wear and damagethrough prolonged use.

[0005] The U.S. Pat. No. 5,320,363 to Burnham discloses a device thatdigs holes of approximately constant diameter. The Burnham patenteddevice has a center shaft and two side shaft brackets and bracket platesplus a single handle with an actuator lever. The relationship betweenthe single handle and the actuator device does not allow for theincreased leverage achieved by the two handles of the instant inventionmaking it more difficult to dig through hard or packed soil and stonyground. It also has multiple parts making maintenance and repair moredifficult.

[0006] Lastly, the following two patents U.S. Pat. No. 5,478,128 toAaland and U.S. Pat. No. 4,042,270 to Weiland are also capable of makingpost holes of constant diameter. These patents also have numerous partswhich can be worn or damaged by use making maintenance and repairs moredifficult, Most of the designs in the prior art have many parts thatbecome worn and damaged from use and the debris generated by digging.The number of parts makes repairs more costly and difficult. Inaddition, several of the designs are awkward to use, especially if useris accustomed to the traditional post hole digger. The present inventionseeks to solve the problems present in the prior art while keeping thedevice simple.

OBJECTS OF THE INVENTION

[0007] Accordingly, it is an object of the present invention to design apost hole digger that makes holes of uniform diameter with a minimumnumber of parts.

[0008] It is an additional object of the present invention to provide adevice that make holes using similar motions of the more traditionalhole diggers.

[0009] It is a further object of the present invention to provide adevice that is durable, easy to use and efficient.

[0010] Further, it is an object of the present invention to provide adevice of novel design and construction.

[0011] Lastly it is an object of the present invention to provide adevice able to dig deep holes without increasing the diameter of theupper portion of the hole.

SUMMARY OF THE INVENTION

[0012] The present invention is able to dig a hole five to six incheswide and three to four feet deep without appreciably enlarging the topsection of the hole. The present device is comprised of a pair ofhandles, two metal scoops and a hinge bracket. In an alternativeembodiment, the device may comprise two unitary pieces incorporating thehandle and scoop into one unit with the units joined by a hinge bracket.The hinge bracket is designed to limit the movement from the elongatedhandles and to translate the movement to the scoops.

[0013] In a preferred embodiment the scoops are joined together toprovide strength and limitation of movement. The digging scoops can bejoined together by a bolt or, in a preferred embodiment, one of thescoops may have a fixed protrusion fitted into a slot formed in thesecond scoop to allow a sliding movement of the first scoop to provide amore secure closing of the scoops during the removal of dirt. The hingebracket can be located at any point along the handles. Preferentially,the hinge bracket is positioned near the midpoint of the pair of handlesor, alternatively, between the midpoint of the handles and the diggingscoops. The bracket hinge limits the movement of the handles andtranslates the handle movement to the digging scoops.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1A a shows a side view of an embodiment of the post holedigger where the scoops are held together by a bolt.

[0015]FIG. 1B shows a side view of a preferred embodiment of the posthole digger.

[0016]FIG. 2 shows a top cross section of the hinge bracket.

[0017]FIG. 3A shows the scoops in a preferred embodiment slidablyattached using a bolt-slot sliding union.

[0018]FIG. 3B depicts a pair of unattached scoops.

[0019]FIGS. 4A and 4B show the post hole digger of the instant inventionand a prior art post hole digger, respectively, in operation digging ahole.

DETAILED DESCRIPTION OF THE INVENTION

[0020] The preferred embodiment of the present invention will now bedescribed with reference to accompanying drawings. It will neverthelessbe understood that no limitations of the scope of the invention isthereby intended, such alterations as scale of the parts, materialsused, position of the hinge bracket, color or weight which would fallwithin the spirit and the scope of the invention described herein.

[0021]FIG. 1A shows a side view of an embodiment of the post hole digger14. The post hole digger 14 is comprised of two handles 8 approximatelyfour to six feet long with a diameter of approximated one inch. Blades12 a and 13 a of scoop 28 are fixedly attached at one end of one of eachhandle 8. The handles 8 are wrapped by a hinge bracket 9 attached to thetwo handles. The hinge bracket 9 has a pin 7 that rotates to translatethe minimum motion applied to the handles 8 into movement of the scoops28 allowing the opening and closing of the scoops 28. In a preferredembodiment, the hinge bracket is located at a midpoint on the handleswith the midpoint defined as the point midway between the top of scoop28 and the top of the handles. In an alternative preferred embodiment,the hinge bracket 9 may be located between the midpoint and the top ofthe scoops. In the embodiment shown in FIG. 1A, the scoops are securelyjoined together by a bolt 29. In the present invention it is notnecessary to have the scoop joined but it is a preferred embodiment toprovide strength and restrain movement. It should be recognized that thehandle/scoop component can be fabricated into a single unitary part,such as by forging, with two such unitary parts joined using hingebracket 9 and the scoop attachments noted supra.

[0022]FIG. 1B shows an alternative preferred embodiment of the post holedigger 14. As in FIG. 1A the device has a pair of handles, two diggingscoops and a hinge bracket. The location and function of the hingebracket 9 is as in FIG. 1A. At the end of each handle 8 a scoop blade 12or 13 is fixedly secured. In the upper portion of scoop 12 is fixed bolt11. The upper portion of opposite scoop blade 13 has a slot 10 thatslides forward and backward on the fixed bolt 11. The efficiency andclosing power of the movement of scoop blades 12 and 13 is enhanced bythe sliding of scoop 12 into and away from the fixed scoop 13.

[0023]FIG. 2 shows a cross sectional view of the hinge bracket 9 and thehandles 8 of the post hole digger. The handles 8 are securely attachedto the hinge bracket by a screw 18 that goes through the hinge bracket 9and at least halfway into the diameter of the handle. It is recognizedthat other attachment methods are possible such as a nut and boltcombination or adhesive or rivets. The hinge bracket 9 has a bolt 17going through the middle, between the handles. The bolt 17 rotates totranslate a minimum of motion applied to the handles to the opening andclosing of the scoops for the removal of dirt from the hole. This allowsfor the digging of a hole of uniform diameter in which width is slightlylarger than the distance between opened scoop 28 without appreciablyenlarging the upper portion of the hole. The hinge bracket 9 ispreferably made of hardened steel and the handles 8 of wood. It isrecognized that other durable materials can be used.

[0024]FIG. 3A and B show a side view of the scoops attached andseparated respectively. In FIG. 3A, the arrow 15 shows the direction inwhich scoop blade 13 slides on the fixed bolt 11 by the use of slot 10.The scoop blade 12 is fixed in place while scoop blade 13 is free toslide into or away from scoop blade 13. The scoops of the post holedigger can be made of any material that is suitable for outdoor use anddigging. Preferably the material will be durable, generallynon-corroding and substantially lightweight. Some of the materials thatmay be used include, but are not limited to, wood, fiberglass, aluminum,hardened steel and others. In a preferred embodiment, the scoop bladeswill be made of hardened steel. The material composing the scoop bladescan be varied accordingly to the type of soil being dug such as a loosesandy soil or a hard-packed clay soil. The scoops can be attached to thehandle by pressure insertion or by a bolt or a screw or other methodswell known in the art.

[0025]FIG. 3B depicts the scoops in an alternative embodiment. In thealternative embodiment, both scoops are identical. One side of the upperportion scoop blade 6 a defines a hole 16 through which the fixed bolt11 will be passed. The opposite side of the upper portion of scoop blade6 a defines a slot 10 that will allow for the sliding movement. Once thehole 16 and the slot 10 from each pair of scoop blades 6 a are aligned,the fixed bolt 11 is passed through both holes 16 and is secured. In avariation two bolts 11 may be used to connect the pair of scoops 6 atogether. In either variation, the top of the bolt is wider than thewidth of the slot 10 allowing for stable sliding movement and strongerclosing power. FIG. 3B also depicts a receiving section 32 formed toreceive handle 8.

[0026]FIGS. 4A and 4B depicts the post hole digger of the instantinvention and a prior art post hole digger, respectively, in operation.In FIG. 4A, it can be appreciated that the hole 19 dug by the post holedigger 14 of the present invention is relatively uniform in diameterfrom top to bottom in comparison to the hole dug by the prior art posthole digger 27 where the hole 20 is wider at the top than at the bottom.The prior art post hole digger 27 has two scoop blades 26 and 24 and abolt 25 joining both scoop blades. Both of the scoops are fixed inposition by the bolt 25 whereas in the present invention posthole digger14 has a fixed scoop 12 and a sliding moving scoop 13. The post holedigger 14 of the present invention also has the hinge bracket 9 to limitthe movement of the handles 8. In contrast, with the prior art post holedigger 27, as the hole 20 becomes deeper, the movement of the handles 23becomes wider and more extreme creating a tapered hole rather the moreuniform hole 19 fashioned by post hole digger 14 of the instantinvention.

What it is claimed is:
 1. A hole digger for making uniform diameterholes, comprising: two elongated handles each with a first end and asecond end, a digging scoop fixedly attached to the first end of eachhandle, and a hinge bracket securely attached on and between each ofsaid handles.
 2. A hole digger according to claim 1 wherein saidelongated handles are made of wood and approximately 4 to 6 feet long.3. A hole digger according to claim 1 wherein said digging scoops aremade of hardened steel.
 4. A hole digger according to claim 1 whereinsaid hinge bracket is located at a midpoint between said second end ofeach of said elongated handles and the top of said scoop.
 5. A holedigger according to claim 1 wherein said hinge bracket is locatedbetween the top of said scoops said midpoint of said elongated handles.6. A hole digger according to claim 1 wherein said handles are removablysecured to said hinge bracket by a screw.
 7. A hole digger according toclaim 1 wherein said hinge bracket is made of hardened steel.
 8. A holedigger for making uniform diameter holes, comprising: two elongatedhandles each with a first end and a second end, a digging scoop fixedlyattached to the first end of each handle, and a hinge bracket securelyattached on and between each of said handles, wherein said diggingscoops are movably joined to each other.
 9. A hole digger according toclaim 8 wherein said elongated handles are made of wood and areapproximately 4 to 6 feet long.
 10. A hole digger according to claim 8wherein said hinge bracket is located at a midpoint between the saidsecond ends of each of said elongated handles and the top of said scoop.11. A hole digger according to claim 8 wherein the said hinge bracket islocated between the top of said scoops and the midpoint of saidelongated handles.
 12. A hole digger according to claim 8 wherein saiddigging scoops are made of hardened steel.
 13. A hole digger accordingto claim 8 wherein said hinge bracket is removably secured to each ofsaid two handles by a screw.
 14. A hole digger according to claim 8wherein said hinge bracket is made of hardened steel.
 15. A hole diggeraccording to claim 8 wherein said scoops are securely joined by a bolt.16. A hole digger according to claim 8 wherein said scoops are made offiberglass.
 17. A hole digger according to claim 8 wherein the upperportion of each of said digging scoops has a first side which defines aslot and a second side which defines a hole for a protrusion
 18. A holedigger of claim 17 wherein said protrusion is a bolt.
 19. A hole diggeraccording to claim 18 wherein the said bolt has a head wider that thesaid slot of the said second scoop.
 20. A hole digger according to claim8 wherein one of said digging scoops has at least one protrusion on theupper portion of said scoop, a second digging scoop has at least oneslot defined by the upper portion of said second scoop wherein said atleast one protrusion passes through and slides along said at least oneslot allowing for sliding movement of the said second scoop.
 21. A holedigger of claim 20 wherein said protrusion is a bolt.
 22. A hole diggeraccording to claim 21 wherein the said bolt has a head wider than saidslot of the said second scoop.
 23. A hole digger for making uniformdiameter holes comprising: two elongated unitary parts each with twoends wherein one end is formed into a digging scoop and the remainingportion is formed into an elongated handle; and a hinge bracket securelyattached on and between each of said handles.
 24. The hole digger ofclaim 23 wherein said hinge bracket is located at a midpoint between theend of each of said elongated handles and the top of said scoops. 25.The hole digger of claim 23 wherein said hinge bracket is locatedbetween the said end where the said scoops are formed and the midpointof said elongated handles.
 26. The hole digger of claim 23 wherein saiddigging scoops are securely joined to each other.
 27. The hole digger ofclaim 26 wherein the upper portion of each of said digging scoops has afirst side which defines a slot and a second side which defines a holefor a bolt.
 28. A hole digger according to claim 25 wherein one of saiddigging scoops has at least one protrusion on the upper portion of saidscoop, a second digging scoop has at least one slot defined by the upperportion of said second scoop wherein said at least one protrusion passesthrough and slides along said at least one slot allowing for slidingmovement of the said second scoop.
 29. A hole digger of claim 27 whereinsaid at least one protrusion is a bolt.
 30. A hole digger according toclaim 28 wherein the said bolt has a head wider that the said slot ofthe said second scoop.